1. Field of the Invention
The field of the invention relates generally to valves in an intake manifold of an internal combustion engine.
2. Background of the Invention
Various types of valves are used in the intake manifold of internal combustion engines for adjusting the intake manifold flow dynamics. One such example is a charge motion control valve (or CMCV), which adjusts the intake flow swirl or tumble, thereby changing combustion characteristics. Another example is a swirl control valve (SCV). Still other examples can be found.
In one application, these valves can be controlled via an electric motor with position feedback. This position, or angle, feedback value of the valve can then be used to diagnose degradation of the valve system. E.g., if actual position/angle does not follow the command, degradation can be detected.
However, such an approach may not detect degradation of the entire valve system. For example, the coupling, or linkage, between the motor and the valve may become disconnected, and such an approach may still indicate acceptable performance between the motor position is moving as commanded, even though the valve itself is not moving.
One approach considered to solve this problem was to use two Hall effect sensors, one for each shaft, to accomplish the determination of de-coupling between the motor and valve shaft.
However, the present inventors have recognized that such an approach adds significant cost to the vehicle.